Abstract

SIP already provides the ability to perform hop-by-hop traceroute
for SIP messages using the Max-Forwards header field, in order to
determine the reachability path of requests to a target. A
mechanism for media-loopback calls has also been defined separately,
which enables test calls to be generated which result in media being
looped back to the originator. This document describes a means of
performing hop-by-hop traceroute-style test calls using the media-
loopback mechanism, in order to test the media path when SIP
sessions go through media-relaying B2BUAs.